The surface membrane properties, particularly the glycoprotein composition, of 3T3, SV40-transformed 3T3, revertant variants of SV40-transformed 3T3 cells which have regained contact inhibition of growth, and murine sarcoma virus-transformed 3T3 cells will be examined. Special attention will be paid to the structure and biological function of the substrate-attached glycoproteins which are deposited on the substrate subsequent to EGTA-mediated removal of cells and which appear to mediate cell-to-substrate adhesion. The mechanisms of binding of these macromolecules to different substrates and to different cell types will be determined with the eventual goal of demonstrating the mechanisms by which transformed cells can be partially reverted to cells with "normal" behavior patterns by growth on 3T3 or revertant substrate-attached glycoproteins. Similar types of glycoproteins will be sought as mediators of cell-to-cell adhesion with an ultimate goal of phenotypically converting transformed cells into growth-inhibited normally-behaving cells by treatment with purified macromolecules. Several approaches to quantitating behavior patterns by normal and virus-transformed cells will be attempted. Enriched preparations of surface and intracellular membranes from normal, virus-transformed, and revertant cells will be analyzed for their protein, glycoprotein, sialylated glycoprotein, and lactoperoxidase-iodinatable proteins to determine what correlations in composition can be made between growing normal and transformed cells and between growing and growth-inhibited normal cells in order to identify components which may be important in growth-control of normal cells and its loss by transformation with oncogenic DNA or RNA viruses. BIBLIOGRAPHIC REFERENCES: Gershman, H., J. Drumm, L. Culp. Sorting out of normal and virus-transformed cells in cellular aggregates. J. Cell Biol. 68, 276, 1976. Culp, L.A. and J.F. Buniel. Substrate-attached serum and cell proteins in adhesion of mouse fibroblasts. J. Cell. Phys. 88, 89, 1976.